Annual COVID-19 booster shots 'likely' necessary, Pfizer CEO says

COVID-19 booster shots could be in our future, health officials say. 

Pfizer CEO Albert Bourla and Dr. Anthony Fauci, the nation's leading infectious disease expert, both said that an annual vaccine may be needed to protect against the coronavirus — similar to the seasonal flu shot.

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Pfizer and BioNTech are studying how long the protective immunity from their vaccine will last. The results will determine whether additional shots will be needed, NBC News reported, though Bourla said boosters are "likely."

"There are vaccines like polio where one dose is enough, and there are vaccines like flu that you need every year," Bourla said in a forum hosted by CVS Health. "The COVID virus looks more like the influenza virus than the polio virus."

Earlier this month, the companies said their vaccine offers high levels of protection six months after the second dose, and was found to be effective against the known COVID-19 variants. 

Moderna also is looking into its vaccine's lasting immunity, and CEO Stéphane Bancel said the company is working on a combined COVID-19 and flu vaccine for annual protection from both illnesses. 

"What we're trying to do at Moderna, actually, is to get a flu vaccine in the clinic this year and then combine a flu vaccine to a COVID vaccine so that you only have to get one boost at your local CVS store, at your GP every year, that will protect you to a variant of concern against COVID and a seasonal flu strain," Bancel told CNBC.

Still, Dr. Scott Hensley, an immunologist at the University of Pennsylvania, has said the two mRNA vaccines — the Pfizer and Moderna shots — may provide protection for years. 

"These mRNA vaccines — it really seems the level of antibodies they elicit are so high, they are persistent," he told CNN earlier this month. "And the combination of having very high levels of antibodies and persistent levels of protection are the recipe for a very long level of protection against these variants. I would not be surprised if this is a vaccine that we only get once." 

Fauci said earlier this week that vaccine makers need to follow people closely to determine when the level of efficacy or protection diminishes.

"If it turns out [to last] a year or a year and a half, we very well may need to get booster shots to keep up the level of protection," Fauci told CNBC. Even if that protection lasts two or three years, he said a booster shot would be useful to protect against the rapidly spreading variants.

A White House official told Reuters that the government is preparing for that possibility. 

So far, about 23% of the United States population is fully vaccinated for COVID-19, according to the Centers for Disease Control.